[swordswinger12]

There is a lower bound by Bennett et al. ("Strengths and weaknesses of quantum computing", SIAM JoComputing 1997) that shows Grover's algorithm is optimal for the generic search problem, so further lowering the asymptotic runtime is probably impossible.

EDIT: Also note that quantum cryptanalytic attacks may be able to break specific symmetric ciphers by exploiting some structure specific to the cipher. But you're correct that QCs don't generically break symmetric cryptography.